Refactoring

lib/rooms/ImageViewerRoom.js

 /* eslint-env node */
 
-const TASKS = [{
-    imageUrl: "images/Brueghel-The_Dutch_Proverbs.jpg",
-    taskDescription: "Suchen Sie nach bildlichen Darstellungen niederländischer Sprichwörter des 16. Jahrhunderts.",
-    taskSource: "Pieter Bruegel the Elder, Netherlandish Proverbs (Oil on oak wood, 1599), Gemäldegalerie, Berlin",
-    duration: 30000,
-  }],
-  MAX_GAZE_POINT_AGE = 2000,
+const MAX_GAZE_POINT_AGE = 2000,
   GAZE_POINT_UPDATE_DELAY = 250;
 
 const colyseus = require("colyseus"),
@@ -16,7 +10,8 @@ const colyseus = require("colyseus"),
   Task = require("../logic/Task.js"),
   ImageViewerState = require("../logic/ImageViewerState.js");
 
-var availableTasks,
+var tasks = Task.getTasks(), 
+  availableTasks,
   currentTask,
   currentTaskIndex,
   gazePoints,
@@ -37,9 +32,9 @@ class ImageViewerRoom extends colyseus.Room {
 
   createTasks() {
     availableTasks = [];
-    for (let i = 0; i < TASKS.length; i++) {
-      availableTasks.push(new Task(TASKS[i].imageUrl, TASKS[i].taskDescription,
-        TASKS[i].taskSource, TASKS[i].duration));
+    for (let i = 0; i < tasks.length; i++) {
+      availableTasks.push(new Task(tasks[i].imageUrl, tasks[i].taskDescription,
+        tasks[i].taskSource, tasks[i].duration));
     }
     currentTaskIndex = 0;
   }
@@ -76,18 +71,24 @@ class ImageViewerRoom extends colyseus.Room {
     this.setTask();
   }
 
+  // Run on each tick (~30FPS)
   update() {
     let now = Date.now();
+    // Remove old gaze points
     this.updateGazePoints(now);
+    // Sanity check to prevent empty updates to subscribers
+    if(gazePoints.length === 0) {
+      return;
+    }
+    // Sanity check to prevent high frequency gaze updates to subscribers
     if(now - lastGazePointUpdate < GAZE_POINT_UPDATE_DELAY) {
       return;
     }
     for (let i = 0; i < gazeSubscribers.length; i++) {
-      let client = gazeSubscribers[i];
       Logger.log(`${gazePoints.length} gaze points available`);
-      if (client && gazePoints.length > 0) {
-        Logger.log(`Sending ${gazePoints.length} gaze points to subsriber`, "ImageViewer Room");
-        this.send(client,{
+      if (gazeSubscribers[i]) {
+        Logger.log(`Sending ${gazePoints.length} gaze points to subscriber`, "ImageViewer Room");
+        this.send(gazeSubscribers[i],{
           type: "gazelist",
           data: gazePoints,
         });
@@ -109,11 +110,14 @@ class ImageViewerRoom extends colyseus.Room {
 
   setTask() {
     Logger.log("Sending current task to state", "ImageViewrRoom");
+    // Cycle through available tasks
     currentTaskIndex += 1;
     if (currentTaskIndex >= availableTasks.length) {
       currentTaskIndex = 0;
     }
     currentTask = availableTasks[currentTaskIndex];
+    // Send task to state to auto update clients
+    // Set listener for task change event (is based on task's duration property)
     this.state.setTask(currentTask, this.onTaskFinished.bind(this));
   }
 }